1. Technical Field
The present invention relates to a method of manufacturing an electronic component mounting body, an electronic component mounting body, and an electro-optical device.
2. Related Art
In general, for various electronic apparatuses, an electronic component such as a semiconductor IC is mounted on a circuit board to constitute a part of an electronic circuit. There are several methods in mounting the electronic component on the circuit board. For example, as a most typical one, a method is known in which a plurality of bumps of the electronic component are connected to a conductive pad on the circuit board, and under this state, under-fill resin is filled and encapsulated between the electronic component and the conductive pad.
In addition, as a mounting method widely used in a liquid crystal display device and the like, a method was provided in which an electronic component is mounted using an anisotropic conductive film (ACF) therebetween. In this method, by using the ACF in which minute conductive particles are dispersed into a thermosetting resin, the electronic component is heated with a heated and pressured head and intrusively pressed onto a glass substrate constituting a circuit board or a liquid crystal panel. The bumps of the electronic component and the terminal on the substrate are conductively connected through conductive particles, and the thermosetting resin is cured and the conductive connection is maintained under the above state.
In addition, a method of manufacturing an electronic component mounting body is known in which a circuit board with a conductive pad formed on one surface of the base material made of thermoplastic resin is prepared, and an IC chip with a plurality of bumps is heated and pressed onto a surface on the opposite side of the conductive pad forming surface of the circuit board so that the bumps are inserted into the thermoplastic resin of the circuit board and fixed with an end thereof conductively connected from inside of the circuit board to the conductive pad (for example, see Japanese Unexamined Patent Application Publication No. 2003-124259).
However, the above-described conventional mounting methods have the following problems. For example, for the method of filling the under-fill resin between the electronic component and the circuit board, injecting the under-fill resin takes a lot of trouble, and a void is easily generated in the under-fill resin around the bumps so that electrical reliability is reduced. In addition, for the mounting method using the ACF, as a pitch between the terminals is reduced, the conductive particles need to be small accordingly, leading to an expensive ACF itself and a short circuit between the terminals due to a bridge of the conductive particles.
For the method described in Japanese Unexamined Patent Application Publication No. 2003-124259, the afore-mentioned problems such as void of the resin and short circuit between the terminals do not occur, so that the terminal having a narrow pitch can be stably mounted on the substrate. However, the present inventors repeatedly conduct a study over the mounting method, which turns out the following facts to be improved.
In other words, the IC chip needs to be fixed on the substrate, as well as connected to the wiring formed on the related substrate, but when the IC chip is heated while pressed onto the substrate, position accuracy of the terminal is easily distorted due to a dimensional change of the thermoplastic resin having a high coefficient of thermal expansion. For this reason, the alignment between the bumps of the IC chip and the conductive pad (wiring) is hardly obtained. In addition, when resin residue is left between the end of the bump inserted into the substrate and the conductive pad, the bump and the conductive pad might not be perfectly connected. As such, in the conventional method of manufacturing the electronic component mounting body, new improvement is required in terms of production yield and mounting efficiency.
The present invention is contrived under these circumstances, and an object of the present invention is to provide a method of manufacturing an electronic component mounting body for mounting the electronic component on the circuit board easily and effectively with high electrical reliability at low costs.